The overall objective of the proposed research is to develop and validate a hearing screening instrument for use in occupational health. This instrument will combine information about an individual's functional hearing ability as determined from HINT thresholds, with acoustic information about the noise environments where hearing-critical tasks occur. These two types of information will be combined to predict the individual's functional hearing abilities in the actual noise environments of the job. The acoustic information will be processed for this purpose using the Extended Speech Intelligibility Index (ESII). In Phase I research, the ESII model for prediction of speech intelligibility in non-stationary real-world noise environments will be validated by comparing predicted and measured performance of normally hearing individuals in recorded noise environments reproduced in the laboratory. The ESII model will then be combined with HINT thresholds to validate similar predictions for hearing impaired individuals. In Phase II research, this model, utilizing both the ESII model and HINT data, will be applied to a wide range of hearing-critical tasks and noise environments. Recommendations of Job Content Experts (JCEs) will be used to set screening criteria for each job. The HINT protocol, ESII data for each noise environment, and the screening criteria will be combined in a prototype screening instrument for field testing and validation in occupational health clinics. In Phase III, Compreval will market this instrument to occupational health clinics and hearing clinics engaged in hearing screening for jobs with hearing-critical tasks. The proposed instrument represents a paradigm shift in occupational hearing screening by measuring hearing ability of normal and hearing impaired subjects in job-related real world noise environment. PUBLIC HEALTH RELEVANCE: The proposed research will produce an innovative and technologically advanced computer-based instrument for objective hearing screening by occupational health physicians of individuals who are required to perform hearing-critical tasks as part of their job. The test will measure functional hearing ability in a real world noise environment corresponding to the test subject's specific job.